Ext not ringing

helllo,

i have asterisk (1.2.27) with freepbx (2.5.1.0)

i have few queues and ring strategy is “ringall”.

the problem: random extension not ringing after successful call, between 30 seconds and 3 minutes

“warp up time” = 0 (it doesn’t matter what i am doing there, it not changing a bit to my problem)

please help.